Two types of mixed-mode fatigue crack growth tests are described. Experimental observations of non-planar fatigue crack growth are compared with numerical predictions from the computer code, FRANC3D. In these analyses, the evolution of crack shape is not assumed a priori. The code predicts evolving fatigue crack shapes and fatigue crack growth rates based on linear-elastic mixed-mode stress intensity factor distributions along the evolving crack fronts. The simulations are shown to result in accurate crack front shape predictions, and to predict overall fatigue crack life in a reasonable and/or conservative manner.